Monitoring systems and methods for monitoring a condition of a patient

ABSTRACT

Monitoring system configured to provide a health chart on an operator display. The health chart includes a plurality of indicators that identify patient parameters. The plurality of indicators form a column that extends parallel to a first axis. The health chart also includes linear projections that are aligned with respective indicators and extend parallel to a second axis that is perpendicular to the first axis. The linear projections represent values of the patient parameters that correspond to the respective indicators. The values are determined by the physiological data obtained from corresponding sensors. The patient monitoring system is configured to determine lengths of the linear projections based on the physiological data. The lengths extend from proximal ends of the linear projections to distal ends of the linear projections. The distal ends move parallel to the second axis toward or away from the respective indicators to change the length.

BACKGROUND

The subject matter herein relates generally to patient monitoringsystems and methods, and more particularly, to patient monitoringsystems and methods that monitor multiple parameters to facilitateidentifying alarm conditions.

Patient monitoring systems are configured to receive physiological datafrom a patient, analyze the physiological data, and communicateinformation to a healthcare provider so that the healthcare provider mayassess a condition of the patient. Monitoring systems may include one ormore sensors that detect the physiological data and an operator displaythat presents the information to the healthcare provider. Theinformation includes recognizable physiological parameters that thehealthcare provider may use to determine a health status or condition ofthe patient. Non-limiting examples of these parameters include heartrate, blood pressure, electrocardiographic (ECG) data, auditory evokedpotentials, and electroencephalogram (EEG) data. ECG data, inparticular, may be used to diagnose certain cardiac conditions, such ascomplex arrhythmias, myocardial ischemia, and prolonged QT intervals.EEG data may be used to assess a patient's depth of sedation (or depthof anesthesia). Diagnosing the above conditions often includessimultaneously analyzing multiple parameters. This diagnosis is mademore difficult because the values that may be considered problematicdepend upon the patient.

Monitoring systems are often particularly configured for monitoringcertain conditions. For example, monitoring systems exist for detectingECG data and analyzing the ST-segments from the ECG data. Changes inST-segments may indicate myocardial ischemia in which blood flow to thepatient's heart is reduced. Traditional ST-segment monitoring systemspresent a table to the healthcare provider. For example, the healthcareprovider may be presented with a table having eleven values that can bepositive or negative and are updated in real-time. Although theseST-segment monitoring systems provide useful information for assessing apatient's health, it is often difficult to interpret the informationquickly. Because they can be difficult or frustrating to use, somehealthcare providers decide not to use the systems.

Another, more recent, ST-segment monitoring system displays twomulti-axis portraits or maps of the ST-segment data. In each portrait,six axes intersect one another at a center of the portrait and each axisintersects a perimeter of the portrait. The ends of the axes, which arepositioned along the perimeter of the portrait, correspond to theplacement of the electrodes used to obtain the ECG data from thepatient. While monitoring a patient, colored sections are shown on theportrait that indicate areas of the heart that are ischemic. Again,although this ST-segment monitoring system provides useful informationfor assessing a patient's status, the portraits are not intuitive and itis often difficult to interpret the information quickly and/orcorrectly. A substantial amount of education may be necessary so thatthe healthcare provider will feel comfortable using the system.

BRIEF DESCRIPTION

In an embodiment, a monitoring system configured to monitor a conditionof a patient is provided. The monitoring system includes a plurality ofsensors that are configured to operably couple to a patient to detectphysiological data from the patient. The patient monitoring system alsoincludes an operator display that is configured to present a monitoringwindow that includes viewable information that is based on thephysiological data of the patient. The patient monitoring system alsoincludes a processor that is configured to execute programmedinstructions stored in memory. The processor, when executing theprogrammed instructions, performs the following operations. Theprocessor receives the physiological data from the patient and providesa health chart in the monitoring window that includes a plurality ofindicators that identify corresponding patient parameters. The pluralityof indicators form a column that extends parallel to a first axis. Thehealth chart also includes linear projections that are aligned withrespective indicators and extend parallel to a second axis that isperpendicular to the first axis. The linear projections represent valuesof the patient parameters that correspond to the respective indicators.The values are determined by the physiological data obtained fromcorresponding sensors. The processor determines corresponding lengths ofthe linear projections based on the physiological data. Thecorresponding lengths extend from proximal ends of the linearprojections to distal ends of the linear projections. The distal endsmove parallel to the second axis to change the length of thecorresponding linear projection.

Optionally, the lengths of the linear projections may be scaled relativeto a maximum length if the patient parameter is less than a designatedthreshold. Upon one of the patient parameters obtaining the designatedthreshold, the lengths of the other linear projections may be scaledrelative to the value of the patient parameter that obtained thedesignated threshold.

In certain aspects, the indicators and corresponding linear projectionsform a plurality of groups in which each group includes multipleindicators and the corresponding linear projections. Each group isvisually differentiated from at least one other group. Optionally, atleast two of the groups correspond to different anatomical regions ofthe heart. Optionally, during an alarm event, the linear projections ofa first group extend designated distances away from the correspondingindicators in a first direction and the linear projections of a secondgroup extend designated distances away from the corresponding indicatorsin a second direction that is opposite the first direction.

In an embodiment, a method is provided that includes receivingphysiological data from a patient and determining values for a pluralityof patient parameters. The values are a function of the physiologicaldata. The method also includes displaying a health chart on an operatordisplay. The health chart includes a plurality of indicators thatidentify corresponding patient parameters. The plurality of indicatorsform a column in the health chart that extends parallel to a first axis.The health chart also includes linear projections that are aligned withrespective indicators and extend parallel to a second axis that isperpendicular to the first axis. The method also includes determiningcorresponding lengths of the linear projections. The lengths of thelinear projections represent the values of the patient parameters thatcorrespond to the respective indicators. The corresponding lengthsextend from proximal ends of the linear projections to distal ends ofthe linear projections. The distal ends move parallel to the second axistoward or away from the respective indicators to change the length ofthe corresponding linear projection.

In an embodiment, a monitoring system configured to monitor a conditionof a patient is provided. The monitoring system includes a plurality ofelectrodes configured to couple to a patient to detectelectrocardiographic (ECG) data of the patient. The monitoring systemalso includes an operator display that is configured to present amonitoring window to a user. The monitoring window includes viewableinformation that is based on the ECG data. The monitoring system alsoincludes a processor configured to execute programmed instructionsstored in memory. The processor, when executing the programmedinstructions, performs the following operations. The processor receivesthe ECG data from the patient and provides a health chart in themonitoring window that includes a plurality of indicators that identifycorresponding ECG leads. The plurality of indicators form a column thatextends parallel to a first axis. The health chart also includes linearprojections that are aligned with respective indicators and extendparallel to a second axis that is perpendicular to the first axis. Thelinear projections represent ST-segment deviations of the ECG leads thatare determined by the ECG data obtained from the correspondingelectrodes. The processor also determines corresponding lengths of thelinear projections based on the ST-segment deviations. The correspondinglengths extend from proximal ends of the linear projections to distalends of the linear projections. The distal ends move parallel to thesecond axis to change the length of the corresponding linear projection.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram of an exemplary system for displaying waveforminformation in accordance with one embodiment.

FIG. 2 illustrates a health chart that may be presented to a user of thesystem of FIG. 1. The health chart in FIG. 2 includes information abouta patient during a steady state or baseline condition.

FIG. 3 illustrates the health chart of FIG. 2 when the patient isprogressing toward an alarm condition.

FIG. 4 illustrates the health chart of FIG. 2 when the patient is in analarm condition.

FIG. 5 illustrates a health chart that may be presented to a user of thesystem of FIG. 1 in accordance with an embodiment.

FIG. 6 illustrates a method of monitoring a patient in accordance withan embodiment.

FIG. 7 illustrates a health chart that may be presented to a user of thesystem of FIG. 1 in accordance with an embodiment.

DETAILED DESCRIPTION

Exemplary embodiments that are described in detail below provide systemsand methods that analyze physiological data that may be used to diagnosea patient of a particular condition. Although the various embodimentsmay be described in connection with electrocardiography, the systems andmethods described herein are not limited to electrocardiographic (ECG)analysis. Non-limiting examples of other types of analysis thatembodiments may be used in connection with include cardiotocographicanalysis, electroencephalographic (EEG) analysis, electromyographicanalysis, depth of sedation, among others. Embodiments may be used formore than one type of analysis (e.g., ECG and depth of sedation).Physiological information displayed by embodiments described herein mayrelate to, for example, electrical activity, blood pressure, heart rate,body temperature, respiratory rate, depth of sedation score, orintrauterine pressure.

At least one technical effect of various embodiments includes providinga health chart that shows magnitudes of certain values in a manner thatmay enable a healthcare provider to determine a condition of the patientmore quickly than known monitoring systems.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.For example, the phrase “a processor” may include a single processor, amulti-core processor, or a plurality of processors. If a plurality ofprocessors are used, the plurality of processors may be found within asingle unit (e.g., computer) or may be distributed throughout a system,such as in multiple units. If one processor is used, the claims mayrecite the processor as “only a single processor.”

Furthermore, references to “one embodiment” are not intended to beinterpreted as excluding the existence of additional embodiments thatalso incorporate the recited features. Moreover, unless explicitlystated to the contrary, embodiments that “comprise,” “have,” or“include” an element or a plurality of elements that have a particularproperty may also include additional such elements that do not have thatparticular property. Furthermore, when a feature is described as beingbased on a parameter or being a function of a parameter, the term “basedon” or “function of” should not be interpreted as the parameter beingthe sole parameter or primary parameter, but may include the possibilitythat the element is also based on other parameters.

As used herein, the term “physiological signals” may include only onetype of signals or multiple types of signals. For examples,physiological signals may include physiological signals relating to afirst type (e.g., ECG signals) and physiological signals relating to asecond type (e.g., EEG signals, heart rate, pulse oximetry, etc.).

The following detailed description of certain embodiments will be betterunderstood when read in conjunction with the appended drawings. To theextent that the figures illustrate diagrams of the functional blocks ofvarious embodiments, the functional blocks are not necessarilyindicative of the division between hardware circuitry. For example, oneor more of the functional blocks (e.g., modules, processors, ormemories) may be implemented in a single piece of hardware (e.g., ageneral purpose signal processor or random access memory, hard disk, orthe like). Similarly, programs may be stand alone programs, may beincorporated as subroutines in an operating system, may be functions inan installed software package, may be a software surface package that isrun from a computer server remotely, and the like. It should beunderstood that the various embodiments are not limited to thearrangements and instrumentality shown in the drawings.

FIG. 1 is a block diagram of an exemplary monitoring system 100 that isconfigured to monitor a condition of a patient. The monitoring system100 includes a computing device or system 102 that is communicativelycoupled to a user interface 104. The user interface 104 may includeinstruments (e.g., user display), hardware, and software (or acombination thereof) that permit the system 100 to display informationto the user and, in some embodiments, permit the user to provide userinputs or selections. The user may be a healthcare provider, such as adoctor, nurse, or other suitably qualified individual. The userinterface 104 may include an operator display 106 (e.g., monitor,screen, touchscreen, and the like) and an input device 108 (e.g.,keyboard, computer mouse, tracking button, touchscreen, and the like)that is capable of receiving and communicating user inputs to thecomputing system 102. In some embodiments, a device constituting theinput device 108 may also be the device constituting the operatordisplay 106 (e.g., touchscreen). The operator display 106 may beconfigured to show a viewable area that includes a monitoring windowhaving a health chart 105, which is described in greater detail below.The user interface 104 may also be configured to query or prompt theuser of the system 100 for designated information.

The monitoring system 100 may be integrated into one component (e.g., alaptop computer) or may be several components that may or may not belocated near each other. The monitoring system 100 may include sensors110 that are configured to detect physiological data, such as from anindividual (e.g., a patient), and communicate the physiological data tothe computing system 102. In particular embodiments, the sensors 110 areelectrodes configured to detect electrical activity within the patient,such as the electrical activity of the heart and/or brain. Alternativelyor in addition to electrical activity, the sensors 110 may be configuredto detect other physiological data, such as a heart rate, bodytemperature, blood pressure, respiratory rate, intrauterine pressure,etc.

In particular embodiments, the monitoring system 100 detects, analyzes,and displays data relating to ECG and/or EEG. Accordingly, themonitoring system 100 may detect electrical activity of the heart over aperiod of time using electrodes placed on a patient's body (e.g., chest,limbs, head). The electrodes detect the electrical changes on the skinthat arise from the heart muscle depolarizing during each heartbeat or,alternatively, from current in the neurons of the brain. In aconventional 12-lead ECG, ten electrodes are placed on the patient'slimbs and on the surface of the chest. The overall magnitude of theheart's electrical potential is then measured from twelve differentangles (“leads”) and is recorded over a period of time. As such, anoverall magnitude and direction of the electrical depolarization may becaptured throughout multiple cardiac cycles.

The computing system 102 may include or be part of a server system, aworkstation, a desktop computer, a laptop computer, or a personaldevice, such as a tablet computer or a smartphone. However, the aboveare only examples and the computing system 102 may be other types ofsystems or devices. In the illustrated embodiment, the computing system102 includes a system controller 114, which may comprise a controller,processor, or other logic-based device. The system controller 114 mayhave or be communicatively coupled to modules for performing methods asdescribed herein. The modules may include an analysis module 123, adisplay module 124, and a graphical representation module 125. Each ofthe modules 123-125 may be a part of another module or include anothermodule. For example, the graphical representation module 125 may be apart of the display module 124. In addition to the above, there may beseveral other modules or sub-modules of the system controller 114 thatare not shown. Each of the modules 123-125 may be communicativelycoupled to a memory or database 130 and/or communicatively coupled to aremote memory or database 132 via, for example, the internet or othercommunication network. Although the database 130 is shown as beingshared by the modules 123-125, each module 123-125 may have a separatememory or database.

The analysis module 123 is configured to receive the physiologicalsignals from the sensors 110 and analyze the physiological signals. Insome embodiments, the physiological signals from one sensor 110 mayrepresent a patient parameter. For example, the physiological signalsfrom a pulse oximeter may directly correspond to an oxygen level in theblood. In other embodiments, a patient parameter may be based on thephysiological signals from two or more sensors. For example, values ofat least some ECG leads may be based on the physiological signals of twoor more electrodes. Accordingly, the analysis module 123 may alsoprocess the physiological signals from one or more sensors 110 todetermine corresponding patient parameters. In some embodiments, theanalysis module 123 may also analyze the physiological signals and/orthe patient parameters to identify events-of-interest. For example, theanalysis module 123 may analyze the patient parameters to determine whenan alarm condition, such as an ischemic event, has occurred. Theanalysis module 123 may use one or more algorithms to identify theevents-of-interest. If an event-of-interest is identified, the analysismodule 123 may communicate this information to the display module 124and/or the graphical representation module 125 to notify the user.

The display module 124 may operate in conjunction with the analysismodule 123 and/or the graphical representation module 125. For example,the graphical representation module 125 may store graphical objects thatrepresent patient parameters, such as the indicators described below.The display module and/or the graphical representation module 125 maygenerate graphics that correspond to the data provided by the analysismodule 123. For example, the display module and/or the graphicalrepresentation module 125 may generate a linear projection having alength that is based on the data provided by the analysis module 123.The data and corresponding lengths may be re-calculated throughout amonitoring session to give the appearance of real-time monitoring. Insuch embodiments, the data and corresponding lengths may bere-calculated every ten seconds, every five seconds, every threeseconds, every one second, or more frequently. Alternative embodimentsmay re-calculate the data and corresponding lengths every twenty second,thirty seconds, or more. The graphical representation module 125 mayalso be configured to store various graphical objects that provide theoverall appearance of a health chart.

The databases 130 and 132 may store data that can be retrieved by thecomponents or modules of the system 100 and other remotely locatedsystems through the internet or other communication network. Thedatabases 130 and 132 can store data that the modules 123-125 require inorder to accomplish the functions of the modules 123-125. For example,the databases 130 and 132 can store the physiological signals obtainedfrom the sensors 110.

The modules 123-125 (and the system controller 114) include one or moreprocessors, microprocessors, controllers, microcontrollers, or otherlogic based devices that operate based on instructions stored on atangible and non-transitory computer readable storage medium. Forexample, the modules 123-125 may be embodied in one or more processorsthat operate based on hardwired instructions or software applications.The databases 130 and 132 can be or include electrically erasableprogrammable read only memory (EEPROM), simple read only memory (ROM),programmable read only memory (PROM), erasable programmable read onlymemory (EPROM), FLASH memory, a hard drive, or other type of computermemory.

As used herein, the terms “computer” or “computing system” may includeany processor-based or microprocessor-based system including systemsusing microcontrollers, reduced instruction set computers (RISC),application specific integrated circuits (ASICs), logic circuits, andany other circuit or processor capable of executing the functionsdescribed herein. The above examples are exemplary only, and are thusnot intended to limit in any way the definition and/or meaning of theterm “computer” or “computing system.”

The computer or processor executes a set of instructions that are storedin one or more storage elements, in order to process input data andprovide output data in the form of a health chart, among other things.The storage elements may also store data or other information as desiredor needed. The storage element may be in the form of an informationsource or a physical memory element within a processing machine.

The set of instructions may include various commands that instruct thecomputer or processor as a processing machine to perform specificoperations such as the methods and processes described herein. The setof instructions may be in the form of a software program. The softwaremay be in various forms such as system software or application software.Further, the software may be in the form of a collection of separateprograms, a program module within a larger program or a portion of aprogram module. The software also may include modular programming in theform of object-oriented programming. The processing of input data by theprocessing machine may be in response to user commands, or in responseto results of previous processing, or in response to a request made byanother processing machine. The program is compiled to run on designatedoperating systems.

FIG. 2 illustrates an exemplary monitoring window 200 in accordance withan embodiment. The monitoring window 200 is configured to be presentedon an operator display, such as the operator display 106 (FIG. 1). Themonitoring window 200 may span an entirety of a viewable area along theoperator display. In other embodiments, however, the monitoring window200 may only span a portion of the viewable area. The monitoring window200 is oriented with respect to first and second axes 291, 292. Thefirst axis 291 may also be referred to as a vertical axis of themonitoring window 200, and the second axis 292 may also be referred toas a horizontal axis of the monitoring window 200.

The monitoring window 200 includes a health chart 202 having informationthat may be used by the user (e.g., healthcare provider) to monitor andassess a condition of the patient. In an exemplary embodiment, thecondition is a cardiac condition. For example, the user may be able todetermine whether the patient is suffering a cardiac event, such asmyocardial ischemia. However, embodiments may be configured to presentinformation for determining other cardiac conditions or other conditionsof a patient. For example, embodiments may be configured to presentinformation for determining a depth of sedation or depth of anesthesia.In FIG. 2, the health chart 202 is displaying information that indicatesthe patient has a baseline condition (e.g., a non-alarming ornon-concerning condition).

The information presented to the user includes a plurality of indicators204 and a plurality of linear projections 206. Optionally, numericalvalues 210 may also be displayed. The indicators 204 represent oridentify patient parameters that are being monitored by the patientmonitoring system. Each of the linear projections 206 is aligned with arespective indicator 204 and, optionally, a respective numerical value210. The linear projection 206 visually represents the numerical valueof the patient parameter relative to a reference value. The numericalvalue 210 identifies the actual value. Accordingly, in the illustratedembodiment, each patient parameter is represented by a single indicator204, a single linear projection 206, and a single numerical value 210 ata single moment or period in time. It is contemplated, however, that apatient parameter may be represented by more than one indicator 204,more than one linear projection 206, and/or more than one numericalvalue 210 in other embodiments. For example, blood pressure may berepresented by both a diastolic value and a systolic value. In suchinstances, a linear projection may be generated for each of thediastolic and systolic values.

By way of example, the indicator 204 labeled “V1” corresponds to apatient parameter, the ECG lead V1, which is often monitored in 12-leadECG data. A linear projection 206 is aligned with the V1 indicator 204.(The linear projection 206 for the lead V1 is more visible in FIG. 3.)In this case, the linear projection 206 is laterally aligned with the V1indicator 204. The linear projection 206 that is aligned with the V1indicator 204 is aligned with a numerical value 210 of “0.1,” which isalso aligned with the V1 indicator 204. As described in greater detailbelow, the linear projection 206 may have a length that correlates tothe absolute value of the respective numerical value 210. The length mayalso be based on other factors in some embodiments.

As shown, the patient parameters represented by the indicators 204include the leads from 12-lead ECG data. The leads are derived from tenelectrodes positioned on the patient. More specifically, the patientparameters include the six chest leads that detect the depolarizationwave in the frontal plane. These may also be referred to as theprecordial leads and are V1, V2, V3, V4, V5, and V6. Each of the chestleads corresponds to an electrode that has a designated position on thepatient's chest. The patient parameters also include extremity leads I,II, III, aVL, and aVF. Optionally, the extremity lead aVR (not shown)may be displayed. The extremity leads are derived from electrodes thatare positioned on the left and right arm and left and right legs.

Although the patient parameters correspond to patient parameters thatare detected by 12-lead ECG data, it should be understood that otherembodiments may display patient parameters that are based on otherphysiological data and that may be used in assessing a patient's healthstatus. For example, the patient parameters may correspond to data thatis used to determine a depth of sedation. The patient parameters mayinclude those found in EEG data.

In the illustrated embodiment, each of the indicators 204 includes ablock-shaped graphical object with symbols (e.g., text) within theobject. Each of the objects of the indicators 204 has the same size andshape as other objects. The symbols may identify the patient parameter.In other embodiments, the indicators 204 may only include symbols. Forinstance, the indicators 204 may only include text that identifies thepatient parameter.

The indicators 204 are arranged in a column 208 that extends parallel tothe first axis 291. The indicators 204 are stacked substantiallyside-by-side and aligned with one another to form the column 208. Thecolumn 208 is spaced apart from edges of the health chart 202 such thatopen spaces exist on either side of the column 208. More specifically,the health chart 202 includes first edges 216, 218 that extend parallelto each other and the first axis 291, and second edges 220, 222 thatextend parallel to each other and the second axis 292. The distancebetween the first edges 216, 218 represents a width of the health chart202, and the distance between the second edges 220, 222 represents aheight of the health chart 202.

As shown, open spaces 224, 226 exist along opposite sides of the column208. In the illustrated embodiment, the open space 224 is positionedbetween the first edge 216 and the column 208, and the open space 226 ispositioned between the first edge 218 and the column 208. The openspaces 224, 226 may extend along the first axis 291 for an entire heightor length of the column 208. The open spaces 224, 226 are configured toallow the linear projections 206 to lengthen into the open spaces 224,226. In some embodiments, the open spaces 224, 226 are configuredrelative to a maximum length of the linear projections 206. The linearprojections 206 are capable of extending away from the correspondingindicator 204 in a direction that is parallel to the second axis 292. Inthe illustrated embodiment, the linear projections 206 may extend ineither direction (e.g., one or the other, not both). However, it iscontemplated that two linear projections may simultaneously extend awayfrom a common indicator 204 in other embodiments.

As shown, the indicators 204 and the linear projections 206 form aplurality of groups 211, 212, 213 in which each group includes amultiple indicators 204 and the linear projections 206 that correspondto the indicators 204 of the group. In particular embodiment, the groups211-213 are visually differentiated from one another. More specifically,the appearance of the groups 211-213 informs the user or gives theimpression that the patient parameters of one group are more associatedwith one another or grouped closer to one another than the patientparameters of other groups. For example, in the illustrated embodiment,adjacent groups are separated from one another by a spacing 214. Thespacing 214 between the indicators 204 of different groups is greaterthan a spacing between adjacent indicators 204 within the same group. Asshown, the indicators 204 of the group 211 substantially abut eachother. For example, the indicators 204 may touch each other or have anominal gap therebetween. The spacing 214 is greater than the nominalgap. In other embodiments, the distance between adjacent indicators 204may be greater than shown in FIG. 2, but the spacing 214 may be greaterthan this other distance. In FIG. 2, the spacing 214 may also existbetween adjacent linear projections 206 of different groups.

It should be understood, however, that the indicators 204 and/or linearprojections 206 of one group may be visually differentiated with therespective elements of the other groups in different manners. Forexample, the indicators 204 of one group may have a common color, size,and/or font that is different from the color, size, or font,respectively, of the indicators 204 of the adjacent group. As anotherexample, the linear projections 206 of one group may have a commonwidth, color, and/or shape that is different from the width, color, orshape, respectively, of the linear projections 206 of the adjacentgroup. Alternatively or in addition to the above, adjacent groups may beseparated by a boundary line that extends between the adjacentindicators 204 of the different groups and/or the linear projections 206of the different groups. For example, each group may be surrounded by anoutline (e.g., rectangular box) that visually informs the viewer thatthe indicators 204 within the box are associated with each other in somemanner.

The indicators 204 or, more specifically, the patient parameters thatthe indicators 204 represent may be associated with one another in apredetermined manner. For example, in the illustrated embodiment, theindicators 204 of the patient parameters are arranged by regions of theheart. The group 211 corresponds to anterior walls, the group 212corresponds to inferior walls, and the group 213 corresponds to lateralwalls. As such, the groups 211, 212, and 213 are labeled “ANT,” “INF,”and “LAT,” respectively. However, as described above, the groups 211,212, and 213 may be visually differentiated in other manners. In suchembodiments, the indicators 204 may display relationships betweenindividual ST segment measurement deviations such that localizedconditions within the heart can be discerned. In particular, theindicators 204 are arranged to facilitate identifying the onset of ananterior ST segment elevation myocardial infarction (or anterior STEMI).

Accordingly, the patient parameters may be arranged in the health chart202 according to anatomical regions. It should be understood, however,that other types of arrangements may be used. For example, asdemonstrated with respect to FIGS. 3 and 4, embodiments may also arrangethe patient parameters by positive or negative correlations duringdesignated events. More specifically, as demonstrated below, each of theindicators 204 of group 211 will have a positive value and each of theindicators 204 of the group 212 will have a negative value duringanterior STEMI.

In some embodiments, during an alarm event (such as anterior STEMI), thelinear projections 206 of the group 211 extend designated distances awayfrom the corresponding indicators 204 in a first direction. The linearprojections 206 of the group 212 extend designated distances away fromthe corresponding indicators 204 in a second direction that is oppositethe first direction. The first and second directions are oppositedirections that extend parallel to the second axis 292.

In determining whether an event-of-interest is occurring, it may benecessary to make a number of different decisions or to considerseparate factors. In other words, a diagnosis may require considerationof different sub-events. Accordingly, the patient parameters in thehealth chart 202 may be arranged to facilitate determining thesesub-events. For example, anterior STEMI may be readily identified whenthe patient parameters of the anterior walls have substantiallyincreased values and when the patient parameters of the inferior wallshave substantially decreased values. In this example, a first sub-event(or sub-condition) is the patient parameters of the anterior wallshaving substantially increased values. In FIG. 2, the patient parametersfor determining this sub-event are grouped together. The secondsub-event (or sub-condition) is the patient parameters of the inferiorwalls having substantially decreased values. In FIG. 2, the patientparameters for determining this sub-event are grouped together. As such,the user may more readily identify when anterior STEMI is occurringbecause the patient parameters for analyzing the first sub-event aregrouped together and the patient parameters for analyzing the secondsub-event are grouped together. Moreover, the two groups are positionedadjacent to each other so both sub-events may be recognizedsubstantially simultaneously.

FIG. 3 illustrates the health chart 202 when the information indicatesthat the patient is progressing toward an alarm condition (e.g.,myocardial ischemia). In FIG. 3, however, the patient has not yettriggered an alarm and is in a pre-alarm condition (or condition thatwarrants more concern than a baseline condition). As shown, thenumerical values 210 of the groups 211, 212 have changed. The numericalvalues 210 of the group 211 have increased substantially (e.g., becomemore positive), and the numerical values 210 of the group 211 havedecreased substantially (e.g., become more negative). Accordingly,lengths 228 of the linear projections 206 for the groups 211, 212 havesubstantially increased as compared to the lengths in FIG. 2.

Each of the linear projections 206 has a proximal end 230 and a distalend 232. The length 228 of the corresponding linear projection 206extends between the corresponding proximal and distal ends 230, 232. Inthe illustrated embodiment, each proximal end 230 is positioned adjacentto the indicator 204 that the corresponding linear projection 206 isassociated with. Each distal end 232 is positioned away from theindicator 204 that the corresponding linear projection 206 is associatedwith. In one or more embodiments, the proximal end 230 is positionedcloser to the indicator 204 than the distal end 232. In alternativeembodiments, however, one or more of the distal ends 232 may bepositioned closer to the corresponding indicator 204.

In the illustrated embodiment, the distal end 232 is configured to moveparallel to the second axis 292 (as indicated by the bi-directionalarrow 234) to change the length 228 of the corresponding linearprojection 206. In the illustrated embodiment, the distal end 232 movestoward or away from the respective indicators 204. The amount ofmovement (and the length 228 of the corresponding linear projection 206)is based on re-calculated numerical values 210.

In the illustrated embodiment, the lateral position (e.g., positionrelative to the second axis 292) of the numerical values 210 is afunction of the numerical value 210. In some embodiments, the numericalvalue 210 may have a fixed position relative to the distal end 232. Assuch, the numerical value 210 may give the appearance of being tetheredto the distal end 232 of the corresponding linear projection 206. Inother embodiments, however, the numerical value 210 may not have a fixedposition relative to the corresponding distal end 232. For example, thenumerical values 210 may be aligned to form a column (not shown). Thenumerical values may have the same position within the column throughoutthe monitoring session.

Embodiments set forth herein may color code at least one of the linearprojections 206, the indicators 204, or the numerical values 210 basedon the value of the corresponding patient parameter. For example, if thevalue of the patient parameter is under a designated baseline threshold,the linear projection 206, the indicator 204, and/or the numerical value210 may be colored in green. If the value of the patient parameterpasses a designated baseline threshold but is less than an alarmthreshold, the linear projection 206, the indicator 204, and/or thenumerical value 210 may be colored in orange. If the value of thepatient parameter passes the baseline threshold and the alarm threshold,the linear projection 206, the indicator 204, and/or the numerical value210 may be colored in red or yellow. It should be understood that othercolors may be used to represent baseline conditions, pre-alarmconditions, and alarm conditions. Alternatively or in addition to theabove, the linear projections 206, the indicators 204, and/or thenumerical values 210 may flash or the patient monitoring system may givean audible sound. In other embodiments, the linear projections 206, theindicators 204, and/or the numerical values 210 of a corresponding groupmay indicate a pre-alarm or alarm condition if only one of the patientparameters of the groups satisfies a designated condition or a pluralityof the patient parameters satisfy designated conditions.

The thresholds or designated conditions may be values of the patientparameters. The threshold may be a common value (whether negative orpositive) for one or more of the patient parameters. For example, thepre-alarm threshold may be 0.5 and the alarm threshold may be 2.0. Inthis case, the alarm threshold may be +2.0 for the patient parameters ofthe groups 211, 213, and the alarm threshold may be −2.0 for the patientparameters of the group 212. In other embodiments, however, thethresholds for the different patient parameters may be different. Forexample, the alarm threshold for V1 may be 2.0, but the alarm thresholdfor III may be −1.5. In some embodiments, the system enables the user toselect the threshold value. For example, the system may receive userinputs that designated the threshold values.

As described above, the lengths 228 of the linear projections 206 are afunction, at least in part, of the values of the patient parameters thatthe linear projections 206 correspond to. For example, in FIG. 3, eachof the linear projections 206 has a length 228 that is scaled relativeto a maximum length 240, which is shown off of the health chart 202 forillustrative purposes. The maximum length 240 may or may not bepresented to the user in the health chart 202.

In an exemplary embodiment, the maximum length 240 occurs when the valueof the patient parameter is 2.0, which corresponds to 2.0 mm in an ECGgraph. Thus, if the value of the patient parameter is less than thedesignated threshold, the length 228 is based on the ratio of the valueto the designated threshold. As one example, if the maximum length 240is 4 cm on the health chart 202 and the value of the patient parameteris 0.5, then the length 228 is 0.5/2.0 or 0.25 of the maximum length240. In this example, the length 228 when the value is 0.5 is 1 cm(0.25*4 cm).

In FIG. 3, each of the lengths 228 is proportional to the ratio betweenthe value of the corresponding parameter and the designated threshold,which is 2.0. More specifically, each of the lengths 228 is a designatedpercentage of the maximum length 240. Table 1 lists the absolutepercentages for the example shown in FIG. 3. When the absolutepercentage is 0%, the linear projections may have a nominal length. Itis noted that each of the values in Table 1 is less than the designatedthreshold. As described with respect to FIG. 4 and Table 2, in someembodiments, the lengths 228 of the linear projections 206 may also be afunction of another value when the designated threshold is exceeded.

TABLE 1 Percentage Group ST Label Value Formula (Absolute) Anterior V10.8 ((100/2.0) * 0.8) 40% V2 0.5 ((100/2.0) * 0.5) 25% V3 0.6((100/2.0) * 0.6) 30% V4 0.5 ((100/2.0) * 0.6) 30% Inferior II −0.9((100/2.0) * −0.9) 45% III −0.7 ((100/2.0) * −0.7) 35% avF −0.7((100/2.0) * −0.7) 35% Lateral I 0.0 ((100/2.0) * 0.0) 0% V5 0.0((100/2.0) * 0.0) 0% V6 0.1 ((100/2.0) * 0.1) 5% aVL 0.2 ((100/2.0) *0.2) 10%

FIG. 4 illustrates the health chart 202 when the information indicatesthat the physiological data of the patient has triggered an alarmcondition. For example, the V1 and V3 indicators 204 have exceeded analarm threshold of 2.0. The II indicator 204 has reached the alarmthreshold of −2.0. In some embodiments, when the value of a patientparameter is equal to or exceeds an alarm threshold, the linearprojections 206 may have a different color. For example, the V1, V3, andIII indicators 204 may be colored red as indicated by differentcross-sectional hatching. In FIG. 4, the I, V5, V6, and aVL indicators204 have not passed the pre-alarm threshold and are colored in green.The V2, V4, III, and aVF indicators 204 have exceeded the pre-alarmthreshold but have not exceeded the alarm threshold. Accordingly, theV2, V4, III, and aVF indicators 204 are colored in orange as indicatedby different cross-sectional hatching. Although the above describesparticular colors when certain conditions occur, it should be understoodthat a variety of colors may be used.

In some embodiments, the lengths 228 of the linear projections 206 mayalso be a function of another value among the patient parameters. Forexample, the lengths 228 may be scaled relative to the greatest value ofthe patient parameters that has also achieved or passed a designatedthreshold. As shown in FIG. 4, each of the V1, V3, and II indicators 204has passed or achieved the designated threshold. Among these patientparameters, the patient parameter of V1 is the greatest magnitude (e.g.,2.3). Thus, in the illustrated embodiment, the lengths 228 of the otherlinear projections 206 are scaled relative to the value of the patientparameter V1. Table 2 is provided below and provides the lengths of theother patient parameters relative to the length of the patient parameterV1.

TABLE 2 Percentage Group ST Label Value Formula (absolute) Anterior V12.3 ((100/2.3) * 2.3)  100% V2 1.9 ((100/2.3) * 1.9) 82.6% V3 2.1((100/2.3) * 2.1) 91.3% V4 1.8 ((100/2.3) * 1.8) 78.2% Inferior II −2.0((100/2.3) * −2.0) 86.9% III −1.7 ((100/2.3) * −1.7) 73.9% avF −1.8((100/2.3) * −1.8) 78.2% Lateral I 0.2 ((100/2.3) * 0.2)  8.6% V5 0.0((100/2.3) * 0.0)   0% V6 0.1 ((100/2.3) * 0.1)  4.3% aVL 0.2((100/2.3) * 0.2)  8.6%

Accordingly, in some embodiments, the lengths 228 of the linearprojections 206 are scaled relative to a maximum length. However, whenthe value of one of the linear projections 206 obtains the designatedthreshold, the lengths 228 of the other linear projections 206 arescaled relative to the value of patient parameter (or the length of thelinear projection) that obtained the designated threshold.

The above example scales each of the lengths of all of the patientparameters relative to the value of one of the patient parameters. Inother embodiments, the lengths of the patient parameters in one groupmay be scaled relative to the maximum value in the group, if thatmaximum value has exceeded the designated threshold. If the group doesnot have a value that exceeds the designated threshold, then the lengthsmay be scaled relative to the maximum length.

FIG. 5 illustrates a health chart 302 that may be presented to a user ofthe system of FIG. 1 in a monitoring window. The health chart 302 mayinclude similar or identical features of the health chart 202 (FIG. 2).For example, the health chart 302 includes a plurality of indicators 304that identify corresponding patient parameters. The plurality ofindicators 304 form a column 308 that extends parallel to a first axis391. Unlike the health chart 202, the column 308 is offset with respectto linear projections 306 of the health chart 302.

The linear projections 306 are aligned with respective indicators 304and extend parallel to a second axis 392 that is perpendicular to thefirst axis 391. The linear projections 306 visually represent values ofthe patient parameters that correspond to the respective indicators 304.Each of the linear projections 306 has a proximal end 330 and a distalend 332. As shown, each of the proximal ends 330 are positioned on orimmediately adjacent to a graph axis 393 that extends parallel to thefirst axis 391. The graph axis 393 is optional and may not appear on thehealth chart 302 in other embodiments. As described above, the distalends 332 are configured to move toward or away from the graph axis 393based on the physiological data. Although not shown, the health chart302 may also display numerical values that numerically represent thevalue of the patient parameters.

FIG. 6 illustrates a method 400 of monitoring a patient in accordancewith an embodiment. The method 400 includes receiving, at 402,physiological data from a patient. The method 400 also includesdetermining, at 404, values for a plurality of patient parameters. Thevalues are a function of the physiological data. The method 400 alsoincludes displaying or presenting, at 406, a health chart on an operatordisplay. The health chart may be similar or identical to the healthcharts described herein and includes a plurality of indicators thatidentify corresponding patient parameters. The plurality of indicatorsform a column in the health chart that extends parallel to a first axis.The health chart also includes linear projections that are aligned withrespective indicators and extend parallel to a second axis that isperpendicular to the first axis.

The method 400 also includes determining, at 408, corresponding lengthsof the linear projections. The lengths of the linear projectionsrepresent the values of the patient parameters that correspond to therespective indicators. The corresponding lengths extend from proximalends of the linear projections to distal ends of the linear projections.The distal ends move parallel to the second axis to change the length ofthe corresponding linear projection.

The determining, at 408, may include determining, at 410, whether thevalue of one or more patient parameters has exceeded a designatedthreshold. If the values have not exceeded the designated threshold,then the lengths of the linear projections are scaled relative to amaximum length at 412. If, however, one or more of the values haveexceeded the designated threshold, then the method may identify, at 414,which value that exceeded the designated threshold is the greatestvalue. The method 400 may then scale the lengths of the linearprojections based on the greatest value at 416. During a monitoringsession, the method 400 may continue to receive physiological data, at402, and repeatedly re-determine the values of the patient parameters,at 404, and the lengths of the linear projections, at 408. As such, themethod 400 may provide for real-time monitoring of a plurality ofpatient parameters to facilitate determining a condition of a patient.

FIG. 7 illustrates a health chart 502 that may be presented to a user ofthe system of FIG. 1 in a monitoring window. The health chart 502 mayinclude similar or identical features of the health chart 202 (FIG. 2)or the health chart 302 (FIG. 5). For example, the health chart 502includes a plurality of indicators 504 that identify correspondingpatient parameters. The plurality of indicators 504 form a column (orrow) 508 that extends parallel to a first axis 591 and perpendicular toa second axis 592. Unlike the health chart 202, the column 508 extendhorizontally across the health chart 502.

Each of the indicators 504 may be aligned with a linear projection 506.The linear projections 506 extend parallel to the second axis 592, whichis perpendicular to the first axis 591. The linear projections 506visually represent values of the patient parameters that correspond tothe respective indicators 504. Each of the linear projections 506 has aproximal end 530 and a distal end 532. A length 528 of the correspondinglinear projection 506 extends between the corresponding proximal anddistal ends 530, 532. The length 528 is based on the physiological dataobtained from the patient during a monitoring session. In theillustrated embodiment, each proximal end 530 is positioned adjacent tothe indicator 504 that the corresponding linear projection 506 isassociated with. Each distal end 532 is positioned away from theindicator 504 that the corresponding linear projection 506 is associatedwith. The distal end 532 is configured to move parallel to the secondaxis 592 to change the length 528 of the corresponding linear projection506.

The indicators 504 and the corresponding linear projections 506 form aplurality of groups 511, 512, 513 in which each of the groups 511-513includes multiple indicators 504 and the corresponding linearprojections 506. In some embodiments, each of the groups 511-513 isvisually differentiated from at least one other group. For example, thegroups 511-513 have different labels 514-516, respectively. Theindicators 504 of the group 511 are positioned above the label 514, theindicators 504 of the group 512 are positioned above the label 515, andthe indicators 504 of the group 513 are positioned above the label 516.In other embodiments, the labels 514-516 may be positioned above thecorresponding indicators 504. Moreover, a visual divider 520, which isillustrated as a vertical line in FIG. 7, is positioned to indicatewhere the groups 511 and 512 are separated. More specifically, a visualdivider 520 is aligned with an interface 522 between the indicator 504for the patient parameter V4 and the indicator 504 for the patientparameter II. Another visual divider 520 is aligned with an interface522 between the indicator 504 for the patient parameter aVF and theindicator 504 for the patient parameter V5.

It is to be understood that the above description is intended to beillustrative, and not restrictive. For example, the above-describedembodiments (and/or aspects thereof) may be used in combination witheach other. In addition, many modifications may be made to adapt aparticular situation or material to the teachings of the inventionwithout departing from its scope. Dimensions, types of materials,orientations of the various components, and the number and positions ofthe various components described herein are intended to defineparameters of certain embodiments, and are by no means limiting and aremerely exemplary embodiments. Many other embodiments and modificationswithin the spirit and scope of the claims will be apparent to those ofskill in the art upon reviewing the above description. The scope of theinvention should, therefore, be determined with reference to theappended claims, along with the full scope of equivalents to which suchclaims are entitled. In the appended claims, the terms “including” and“in which” are used as the plain-English equivalents of the respectiveterms “comprising” and “wherein.” Moreover, in the following claims, theterms “first,” “second,” and “third,” etc. are used merely as labels,and are not intended to impose numerical requirements on their objects.Further, the limitations of the following claims are not written inmeans—plus-function format and are not intended to be interpreted basedon 35 U.S.C. §112, sixth paragraph, unless and until such claimlimitations expressly use the phrase “means for” followed by a statementof function void of further structure.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they have structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A monitoring system configured to monitor acondition of a patient, the system comprising: a plurality of sensorsconfigured to operably couple to a patient to detect physiological datafrom the patient; an operator display configured to present a monitoringwindow that includes viewable information that is based on thephysiological data of the patient; and a processor configured to executeprogrammed instructions stored in memory, wherein the processor, whenexecuting the programmed instructions, performs the followingoperations: receives the physiological data from the patient; provides ahealth chart in the monitoring window that includes a plurality ofindicators that identify corresponding patient parameters, the pluralityof indicators forming a column that extends parallel to a first axis,the health chart also including linear projections that are aligned withrespective indicators and extend parallel to a second axis that isperpendicular to the first axis, the linear projections representingvalues of the patient parameters that correspond to the respectiveindicators, the values being determined by the physiological dataobtained from corresponding sensors; and determines correspondinglengths of the linear projections based on the physiological data, thecorresponding lengths extending from proximal ends of the linearprojections to distal ends of the linear projections, at least one ofthe proximal end or the distal ends moving parallel to the second axisto change the length of the corresponding linear projection.
 2. Themonitoring system in accordance with claim 1, wherein the values of thepatient parameters correspond to ST-segment deviations.
 3. Themonitoring system in accordance with claim 1, wherein the lengths of thelinear projections are scaled relative to a maximum length if thepatient parameter is less than a designated threshold, wherein, upon oneof the patient parameters obtaining the designated threshold, thelengths of the other linear projections are scaled relative to the valueof the patient parameter that obtained the designated threshold.
 4. Themonitoring system in accordance with claim 1, wherein the indicators andcorresponding linear projections form a plurality of groups in whicheach group includes multiple indicators and the corresponding linearprojections, each group being visually differentiated from at least oneother group.
 5. The monitoring system in accordance with claim 4,wherein at least two of the groups correspond to different anatomicalregions of the heart.
 6. The monitoring system in accordance with claim4, wherein, during an alarm event, the linear projections of a firstgroup extend designated distances away from the corresponding indicatorsin a first direction and the linear projections of a second group extenddesignated distances away from the corresponding indicators in a seconddirection that is opposite the first direction.
 7. The monitoring systemin accordance with claim 4, wherein the groups are configured such that,during an alarm event, the values of the patient parameters of a firstgroup are positive and the values of a second group are negative.
 8. Themonitoring system in accordance with claim 1, wherein the proximal endsare positioned adjacent to the corresponding indicators and the distalends are configured to move toward or away from the correspondingindictors, wherein at least one of the linear projections is configuredto extend in either direction away from the corresponding indicatorbased on the physiological data.
 9. The monitoring system in accordancewith claim 1, wherein the patient parameters correspond to at least oneof electrical activity of the brain, heart rate, blood pressure, orauditory evoked potentials, the health chart presenting information tothe user for monitoring a depth of anesthesia.
 10. The monitoring systemin accordance with claim 1, wherein the first axis is a vertical axisand the second axis is a horizontal axis.
 11. A method of monitoring acondition of a patient, the method comprising: receiving physiologicaldata from a patient; determining values for a plurality of patientparameters, the values being a function of the physiological data;displaying a health cart on an operator display, the health chartincluding a plurality of indicators that identify corresponding patientparameters, the plurality of indicators forming a column in the healthchart that extends parallel to a first axis, the health chart alsoincluding linear projections that are aligned with respective indicatorsand extend parallel to a second axis that is perpendicular to the firstaxis; and determining corresponding lengths of the linear projections,the lengths of the linear projections representing the values of thepatient parameters that correspond to the respective indicators, thecorresponding lengths extending from proximal ends of the linearprojections to distal ends of the linear projections, the distal endsmoving parallel to the second axis toward or away from the respectiveindicators to change the length of the corresponding linear projection.12. The method in accordance with claim 11, wherein the values of thepatient parameters correspond to ST-segment deviations.
 13. The methodin accordance with claim 11, wherein the lengths of the linearprojections are scaled relative to a maximum length if the patientparameter is less than a designated threshold, wherein, upon one of thepatient parameters obtaining the designated threshold, the methodincludes re-scaling the lengths of the other linear projections relativeto the value of the patient parameter that obtained the designatedthreshold.
 14. The method in accordance with claim 11, wherein theindicators and corresponding linear projections form a plurality ofgroups in which each group includes multiple indicators and thecorresponding linear projections, each group being visuallydifferentiated from at least one other group.
 15. The method inaccordance with claim 14, wherein, during an alarm event, the linearprojections of a first group extend designated distances away from thecorresponding indicators in a first direction and the linear projectionsof a second group extend designated distances away from thecorresponding indicators in a second direction that is opposite thefirst direction.
 16. A monitoring system configured to monitor acondition of a patient comprising: a plurality of electrodes configuredto couple to a patient to detect electrocardiographic (ECG) data of thepatient; an operator display configured to present a monitoring windowto a user, the monitoring window including viewable information that isbased on the ECG data; and a processor configured to execute programmedinstructions stored in memory, wherein the processor, when executing theprogrammed instructions, performs the following operations: receives theECG data from the patient; and provides a health chart in the monitoringwindow that includes a plurality of indicators that identifycorresponding ECG leads, the plurality of indicators forming a columnthat extends parallel to a first axis, the health chart also includinglinear projections that are aligned with respective indicators andextend parallel to a second axis that is perpendicular to the firstaxis, the linear projections representing ST-segment deviations of theECG leads that are determined by the ECG data obtained from thecorresponding electrodes; and determines corresponding lengths of thelinear projections based on the ST-segment deviations, the correspondinglengths extending from proximal ends of the linear projections to distalends of the linear projections, the distal ends moving parallel to thesecond axis to change the length of the corresponding linear projection.17. The monitoring system in accordance with claim 16, wherein thelengths of the linear projections are scaled relative to a maximumlength if the corresponding ECG leads are less than a designatedthreshold, wherein, upon one of the ECG leads obtaining the designatedthreshold, the lengths of the other linear projections are scaledrelative to the value of the ECG lead that obtained the designatedthreshold.
 18. The monitoring system in accordance with claim 16,wherein the indicators and corresponding linear projections form aplurality of groups in which each group includes multiple indicators andthe corresponding linear projections, each group being visuallydifferentiated from at least one other group.
 19. The monitoring systemin accordance with claim 18, wherein at least two of the groupscorrespond to different anatomical regions of the heart.
 20. Themonitoring system in accordance with claim 18, wherein, during an alarmevent, the linear projections of a first group extend designateddistances away from the corresponding indicators in a first directionand the linear projections of a second group extend designated distancesaway from the corresponding indicators in a second direction that isopposite the first direction.